This application relates to and claims priority from Japanese Patent Application No. 2000-128256 filed on Apr. 27, 2000.
1. Field of the Invention
The present invention relates to an air passage switching door for opening and closing an air passage through which air flows. More particularly, the present invention relates to a method for manufacturing the air passage switching door for a vehicle air conditioner.
2. Related Art
In a conventional method of an air passage switching door described in U.S. Pat. No. 4,994,226, both stacked packing materials are disposed in a mold space of a forming die, and a melted resin material is injected between both the packing materials to form a door base plate, so that both the packing materials are bonded integrally to both surfaces of the door base plate. However, in this case, thickness of the air passage switching door becomes thicker due to the thickness of both the packing materials, and a pressure loss or an air-blowing noise of the air passage may become larger.
In view of the foregoing problems, it is an object of the present invention to provide an air passage switching door which is formed in low cost using a single packing material while having a reduced thickness.
It is an another object of the present invention to provide a method for readily manufacturing the air passage switching door.
According to the present invention, in an air passage switching door for opening and closing an air passage, a single packing material having a size approximately corresponding to a plate surface of a door base member is used, a rotation shaft is disposed integrally with the door base member at a center portion of the door base member so that the door base member is rotatable around the rotation shaft, and the door base member and the packing material are disposed to be crossed with each other around the rotation shaft in such a manner that, the packing material is bonded onto both one side surface of the first plate portion of the door base member, and onto one side surface of the second plate portion, opposite to the one side surface of the first plate portion. Accordingly, even in the air passage switching door using the single packing material, the packing material can be bonded onto opposite surfaces of the first and second plates, respectively. Therefore, the air passage switching door has a reduced thickness, and is formed in low cost using the single packing material.
According to a method for manufacturing the air passage switching door, the method includes a first step for placing the single packing material having the size approximately corresponding to the door base member in a forming die, and a second step for forming the door base member and the rotation shaft by injecting a melted resin onto both side surfaces of the packing material. In the second step, the melted resin is injected onto one side area of the packing material among one side surface of the packing material, and is injected onto the other side area of the packing material among the other side surface of the packing material, to form the door base member crossed with the packing material. Accordingly, the air passage switching door can be readily manufactured in low cost using the single packing material to have a reduced thickness.
Preferably, in the second step, the melted resin passes through a first communication hole provided at a center portion of the packing material to form a connection portion connecting the first and second plate portions of the door base member. Therefore, the connection portion can be extended obliquely relative to both surfaces of the first and second plate portions.
More preferably, in the second step, the melted resin is injected to the other side surface of the packing material at the other side area of the packing material through a second communication hole provided in the packing material at a position shifted from the center portion. Therefore, it is possible to form the first and second plate portions at both sides of the packing material using one side injection of the melted resin. Accordingly, the injection of the melted resin can be readily performed, and producing performance of the air passage switching door can be improved.